One credit that may be difficult to account for (9)
I believe the answer is:
recondite
'one credit that may be difficult to account for' is the definition.
Both the answer and definition are adjectives. Maybe there's an association between them I don't understand?
'one credit that may be' is the wordplay.
'that may be' indicates an anagram.
'one'+'credit'='onecredit'
'onecredit' anagrammed gives 'RECONDITE'.
Can you help me to learn more?
(Other definitions for recondite that I've seen before include "Mysterious" , "Enigmatic" , "(Of knowledge) obscure" , "Difficult to understand" , "Direct one to be obscure or difficult" .)